[Comparison of shear bond strength of four self- etch and total -etch bondings in dentine of primary teeth; an in vitro study]

ABSTRACT

Conservative procedures using dentine adhesives are one of the important aspects of pediatric dentistry. The bonding performance of current adhesive systems to primary dentine has not been thoroughly researched. The aim of this study was to evaluate shear bond strength of four adhesive systems bonded to primary molars dentine. For this experimental study, 48 extracted primary human molars were collected and stored in normal saline at room temperature. For shear bonding test, the labial or lingual surfaces of the primary molars were used. The flat buccal/lingual surfaces of the teeth were divided into four groups [n=12]. The tested adhesives were Clearfil SE Bond [SE]; Adhese [AS]; Prime and Bond NT [NT] and Exite [EX]. Four dentine adhesives were applied following the manufactures' instructions. Composite [Z100] cylinders [3x4mm] were polymerized on the treated dentine surfaces and specimens were stored in normal salin for 72 hours prior to testing. After themocycling, the teeth were subjected to shear stress using a universal testing machine [Instron] at a crosshead speed of 1mm/min. The results were analyzed with ANOVA and Tukey's HSD test. The shear bond strength values ranged from 4.71 to 26.68 Mpa on dentine, in decreasing order of SE, NT, EX and AS. The differences in bond strengths between the four groups were statistically significant [p =0.0001]. Adhesives systems are technique sensitive and in pediatric dentistry, choice of adhesive system may be affected not only by physical properties of the materials but also by factors related to the method required for their application